<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>localStorage</title>
</head>

<body>
    <h2>localStorage</h2>
    <button onclick="saveData()">点我保存一个数据</button>
    <button onclick="readData()">点我读取一个数据</button>
    <button onclick="deleteData()">点我删除一个数据</button>
    <button onclick="deleteAll()">点我删除所有数据</button>

    <script>
        // localStorage 存的数据，需要手动删除才会消失

        function saveData() {
            localStorage.setItem('msg', 'hello!')   // key 和 value 最后都是字符串，就算是对象，也要 JSON.stringify()
            // 点击玩按钮后，查看浏览器控制台的 Application 里面的 Local Storage
        }
        function readData() {
            alert(localStorage.getItem('msg'));
        }
        function deleteData() {
            localStorage.removeItem('msg')
        }
        function deleteAll() {
            localStorage.clear()
        }
    </script>
</body>

</html>